Mhz, Class d push-Pull, 2kw rf generator with Microsemi drf1300 Power mosfet hybrid

Power and voltage graphs 
Figure 10.
Efficiency vs. Power 
Figure 11.
HV PS vs. Vds 
Efficiency vs Output Pow er
76.0
77.0
78.0
79.0
80.0
81.0
82.0
83.0
84.0
85.0
86.0
87.0
344
486
653
842
939
1044
1152
1270
1400
1500
1630
1770
1950
Pout, W
E
ff.
, %
Vdrain vs Vds
0
100
200
300
400
500
600
100
120
140
160
170
180
190
200
210
220
230
240
250
Vds, V
Vd
ra
in
, V

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Application Note 1812 
September 2011 
www.microsemi.com
10/17 
d.
Vds waveforms for various HV PS voltages 
Figure 12. 
Waveform when HV PS =100V 
Figure 13.
Waveform when HV PS = 150V 

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Application Note 1812 
September 2011 
www.microsemi.com
11/17 
Figure 14.
Waveform when HV PS = 180V 
 
Figure 15.
Waveform when HV PS =220V 

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Application Note 1812 
September 2011 
www.microsemi.com
12/17 
 
Figure 16.
Waveform when HV PS =250V 
CONCLUSION 
This Application Note describes design of a 2KW, 13.56MHz, Class D Push-Pull, RF generator. A Microsemi 
DRF1300 Hybrid was used to overcome layout parasitics that simplified the design and providing a single low cost, 
high efficiency RF generator. Limitations in transformer bandwidth caused this application to exceed the 500V 
breakdown voltage of the MOSFETs while achieving 2KW. Transformer design can be further optimized to 
eliminate the peaking as shown in the Vds waveforms. The principles of this application note can be verified with 
the DRF1300/CLASS-D reference design from Microsemi. The reference design minimizes design time by 
allowing an engineer to evaluate the performance into a 50 Ohm load and provides a platform for more complex 
load matching. 
REFERENCES 
-. Solid State Radio Engineering – Herbert L. Krauss and Charles W. Bostian 
-. Application Note: Simple and Inexpensive High Efficiency Power Amp using New APT MOSFET – Kenneth 
Dierberger 1994 
-. Application Note: 3KW and 5KW Half-Bridge Class-D RF Generator at 13.56Mhz with 89% Efficiency and 
Limited frequency Agility – DEI, Inc 

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Application Note 1812 
September 2011 
www.microsemi.com
13/17